WPP and its media trading platform Xaxis, Interpublic Group, smart TV maker Vizio, ispot.tv, TubeMogul and several other ad tech companies have been slapped with a multimillion dollar class action law suit in U.S. District Court in California for allegedly sharing personally identifiable viewing data culled from Vizio smart TVs in violation of several federal and state laws including the Video Privacy Protection Act and California’s Unfair Competition Law.